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| /*
** 2003 January 11
**
** The author disclaims copyright to this source code. In place of
** a legal notice, here is a blessing:
**
** May you do good and not evil.
** May you find forgiveness for yourself and forgive others.
** May you share freely, never taking more than you give.
**
*************************************************************************
** This file contains code used to implement the sqlite3_set_authorizer()
** API. This facility is an optional feature of the library. Embedded
** systems that do not need this facility may omit it by recompiling
** the library with -DSQLITE_OMIT_AUTHORIZATION=1
*/
#include "sqliteInt.h"
/*
** All of the code in this file may be omitted by defining a single
** macro.
*/
#ifndef SQLITE_OMIT_AUTHORIZATION
/*
** Set or clear the access authorization function.
**
** The access authorization function is be called during the compilation
** phase to verify that the user has read and/or write access permission on
** various fields of the database. The first argument to the auth function
** is a copy of the 3rd argument to this routine. The second argument
** to the auth function is one of these constants:
**
** SQLITE_CREATE_INDEX
** SQLITE_CREATE_TABLE
** SQLITE_CREATE_TEMP_INDEX
** SQLITE_CREATE_TEMP_TABLE
** SQLITE_CREATE_TEMP_TRIGGER
** SQLITE_CREATE_TEMP_VIEW
** SQLITE_CREATE_TRIGGER
** SQLITE_CREATE_VIEW
** SQLITE_DELETE
** SQLITE_DROP_INDEX
** SQLITE_DROP_TABLE
** SQLITE_DROP_TEMP_INDEX
** SQLITE_DROP_TEMP_TABLE
** SQLITE_DROP_TEMP_TRIGGER
** SQLITE_DROP_TEMP_VIEW
** SQLITE_DROP_TRIGGER
** SQLITE_DROP_VIEW
** SQLITE_INSERT
** SQLITE_PRAGMA
** SQLITE_READ
** SQLITE_SELECT
** SQLITE_TRANSACTION
** SQLITE_UPDATE
**
** The third and fourth arguments to the auth function are the name of
** the table and the column that are being accessed. The auth function
** should return either SQLITE_OK, SQLITE_DENY, or SQLITE_IGNORE. If
** SQLITE_OK is returned, it means that access is allowed. SQLITE_DENY
** means that the SQL statement will never-run - the sqlite3_exec() call
** will return with an error. SQLITE_IGNORE means that the SQL statement
** should run but attempts to read the specified column will return NULL
** and attempts to write the column will be ignored.
**
** Setting the auth function to NULL disables this hook. The default
** setting of the auth function is NULL.
*/
int sqlite3_set_authorizer(
sqlite3 *db,
int (*xAuth)(void*,int,const char*,const char*,const char*,const char*),
void *pArg
){
#ifdef SQLITE_ENABLE_API_ARMOR
if( !sqlite3SafetyCheckOk(db) ) return SQLITE_MISUSE_BKPT;
#endif
sqlite3_mutex_enter(db->mutex);
db->xAuth = (sqlite3_xauth)xAuth;
db->pAuthArg = pArg;
sqlite3ExpirePreparedStatements(db, 0);
sqlite3_mutex_leave(db->mutex);
return SQLITE_OK;
}
/*
** Write an error message into pParse->zErrMsg that explains that the
** user-supplied authorization function returned an illegal value.
*/
static void sqliteAuthBadReturnCode(Parse *pParse){
sqlite3ErrorMsg(pParse, "authorizer malfunction");
pParse->rc = SQLITE_ERROR;
}
/*
** Invoke the authorization callback for permission to read column zCol from
** table zTab in database zDb. This function assumes that an authorization
** callback has been registered (i.e. that sqlite3.xAuth is not NULL).
**
** If SQLITE_IGNORE is returned and pExpr is not NULL, then pExpr is changed
** to an SQL NULL expression. Otherwise, if pExpr is NULL, then SQLITE_IGNORE
** is treated as SQLITE_DENY. In this case an error is left in pParse.
*/
int sqlite3AuthReadCol(
Parse *pParse, /* The parser context */
const char *zTab, /* Table name */
const char *zCol, /* Column name */
int iDb /* Index of containing database. */
){
sqlite3 *db = pParse->db; /* Database handle */
char *zDb = db->aDb[iDb].zDbSName; /* Schema name of attached database */
int rc; /* Auth callback return code */
if( db->init.busy ) return SQLITE_OK;
rc = db->xAuth(db->pAuthArg, SQLITE_READ, zTab,zCol,zDb,pParse->zAuthContext
#ifdef SQLITE_USER_AUTHENTICATION
,db->auth.zAuthUser
#endif
);
if( rc==SQLITE_DENY ){
char *z = sqlite3_mprintf("%s.%s", zTab, zCol);
if( db->nDb>2 || iDb!=0 ) z = sqlite3_mprintf("%s.%z", zDb, z);
sqlite3ErrorMsg(pParse, "access to %z is prohibited", z);
pParse->rc = SQLITE_AUTH;
}else if( rc!=SQLITE_IGNORE && rc!=SQLITE_OK ){
sqliteAuthBadReturnCode(pParse);
}
return rc;
}
/*
** The pExpr should be a TK_COLUMN expression. The table referred to
** is in pTabList or else it is the NEW or OLD table of a trigger.
** Check to see if it is OK to read this particular column.
**
** If the auth function returns SQLITE_IGNORE, change the TK_COLUMN
** instruction into a TK_NULL. If the auth function returns SQLITE_DENY,
** then generate an error.
*/
void sqlite3AuthRead(
Parse *pParse, /* The parser context */
Expr *pExpr, /* The expression to check authorization on */
Schema *pSchema, /* The schema of the expression */
SrcList *pTabList /* All table that pExpr might refer to */
){
sqlite3 *db = pParse->db;
Table *pTab = 0; /* The table being read */
const char *zCol; /* Name of the column of the table */
int iSrc; /* Index in pTabList->a[] of table being read */
int iDb; /* The index of the database the expression refers to */
int iCol; /* Index of column in table */
assert( pExpr->op==TK_COLUMN || pExpr->op==TK_TRIGGER );
assert( !IN_RENAME_OBJECT || db->xAuth==0 );
if( db->xAuth==0 ) return;
iDb = sqlite3SchemaToIndex(pParse->db, pSchema);
if( iDb<0 ){
/* An attempt to read a column out of a subquery or other
** temporary table. */
return;
}
if( pExpr->op==TK_TRIGGER ){
pTab = pParse->pTriggerTab;
}else{
assert( pTabList );
for(iSrc=0; ALWAYS(iSrc<pTabList->nSrc); iSrc++){
if( pExpr->iTable==pTabList->a[iSrc].iCursor ){
pTab = pTabList->a[iSrc].pTab;
break;
}
}
}
iCol = pExpr->iColumn;
if( NEVER(pTab==0) ) return;
if( iCol>=0 ){
assert( iCol<pTab->nCol );
zCol = pTab->aCol[iCol].zName;
}else if( pTab->iPKey>=0 ){
assert( pTab->iPKey<pTab->nCol );
zCol = pTab->aCol[pTab->iPKey].zName;
}else{
zCol = "ROWID";
}
assert( iDb>=0 && iDb<db->nDb );
if( SQLITE_IGNORE==sqlite3AuthReadCol(pParse, pTab->zName, zCol, iDb) ){
pExpr->op = TK_NULL;
}
}
/*
** Do an authorization check using the code and arguments given. Return
** either SQLITE_OK (zero) or SQLITE_IGNORE or SQLITE_DENY. If SQLITE_DENY
** is returned, then the error count and error message in pParse are
** modified appropriately.
*/
int sqlite3AuthCheck(
Parse *pParse,
int code,
const char *zArg1,
const char *zArg2,
const char *zArg3
){
sqlite3 *db = pParse->db;
int rc;
/* Don't do any authorization checks if the database is initialising
** or if the parser is being invoked from within sqlite3_declare_vtab.
*/
assert( !IN_RENAME_OBJECT || db->xAuth==0 );
if( db->init.busy || IN_SPECIAL_PARSE ){
return SQLITE_OK;
}
if( db->xAuth==0 ){
return SQLITE_OK;
}
/* EVIDENCE-OF: R-43249-19882 The third through sixth parameters to the
** callback are either NULL pointers or zero-terminated strings that
** contain additional details about the action to be authorized.
**
** The following testcase() macros show that any of the 3rd through 6th
** parameters can be either NULL or a string. */
testcase( zArg1==0 );
testcase( zArg2==0 );
testcase( zArg3==0 );
testcase( pParse->zAuthContext==0 );
rc = db->xAuth(db->pAuthArg, code, zArg1, zArg2, zArg3, pParse->zAuthContext
#ifdef SQLITE_USER_AUTHENTICATION
,db->auth.zAuthUser
#endif
);
if( rc==SQLITE_DENY ){
sqlite3ErrorMsg(pParse, "not authorized");
pParse->rc = SQLITE_AUTH;
}else if( rc!=SQLITE_OK && rc!=SQLITE_IGNORE ){
rc = SQLITE_DENY;
sqliteAuthBadReturnCode(pParse);
}
return rc;
}
/*
** Push an authorization context. After this routine is called, the
** zArg3 argument to authorization callbacks will be zContext until
** popped. Or if pParse==0, this routine is a no-op.
*/
void sqlite3AuthContextPush(
Parse *pParse,
AuthContext *pContext,
const char *zContext
){
assert( pParse );
pContext->pParse = pParse;
pContext->zAuthContext = pParse->zAuthContext;
pParse->zAuthContext = zContext;
}
/*
** Pop an authorization context that was previously pushed
** by sqlite3AuthContextPush
*/
void sqlite3AuthContextPop(AuthContext *pContext){
if( pContext->pParse ){
pContext->pParse->zAuthContext = pContext->zAuthContext;
pContext->pParse = 0;
}
}
#endif /* SQLITE_OMIT_AUTHORIZATION */
|